Hypertext Help with LaTeX

eqnarray

The eqnarray environment is typically used to display a
sequence of equations or inequalities; it may also be used to
manage spacing for long equations. The
\lefteqn command is useful
in this environment for splitting long equations over several
lines.

It is very much like a three-column
array environment, with position
argument rcl, i.e., the columns are justified right,
center, and left, respectively. (However,
\multicolumn may not be
used.)

Consecutive rows are separated by
\\ commands and consecutive
items within a row separated by an &. Any item may
be empty, i.e., no text.

A separate equation number is placed on every line unless
that line has a \nonumber command. The optional
eqnarray* form does not generate any equation numbers.

A \label command anywhere
within a row generates a reference to that row's number.